This invention relates to a selective adsorption process for the separation of gaseous mixtures and in particular wherein a component A of a gaseous mixture is selectively adsorbed compared to a component B whereby a gas enriched in component B is recovered from the adsorption bed, and whereafter the pressure in the adsorption bed is lowered enabling the withdrawal of a gas enriched in component A, the adsorbent being thereby regenerated per se or by further measures.
A process of this type is known from U.S. Pat. No. 3,085,379. This conventional method is directed specifically to the removal of traces of air from helium wherein the helium losses are minimized by recycling a portion of the previously adsorbed components to the feed gas so that the concentration of adsorbable components is increased in the feed gas to obtain a higher loading of the adsorbent as well as a return of desired product into the gas cycle.
However, if this conventional process were to be applied to gaseous mixtures where the objective is not to remove an impurity component by adsorption but rather to obtain at least two components from a gaseous mixture in a maximally pure condition as well as in a maximally quantitative yield, then the conventional process would be inadequate, since it serves merely the purpose of completely removing a component present in relatively minor concentrations from a gas while tolerating more or less large losses of the other, primary component.